Oracle SQL：根据另一个表中给定条件的列中的找到值进行插入

Question

I want to merge my order data into one table which is now in two separate tables: Order ID and customer code in table Orders:

Order_ID  Customer
1         C11
2         C76
4         C32

and order detalis in table Details (with columns Order_ID, Hour, Quantity) in which the ordered quantity for the hours that the order is valid is given:

Order_ID  Hour Quantity
1         2     10
1         3     20
2         2      5
2         3      5
2         4      5
4         6     20
4         7     25

I want to merge data of these two tables in one table to have only one row per each order by inserting the quantity for the hours that the order is valid in corresponding column, otherwise zero.

Order_ID  Cutomer  Hour1 Hour2 Hour3 Hour4 Hour5 Hour6 Hour7 ...
1         C11       0     10    20    0     0     0     0
2         C76       0      5     5    5     0     0     0
4         C32       0      0     0    0     0    20    25

I tried (only for quantity of hour 1):

insert into Merged_Order_Table 
(Order_ID,Customer,Hour1)
select 
Orders.Order_id,Orders.Customer,
case 
when 1 in (select Details.Hour from Details,Orders where 
Details.Order_ID = Orders.Order_ID)
then Details.Quantity
else 0
end
from 
Orders
inner join
Details
on
Details.Order_ID = Orders.Order_ID;

But got quantity in Hour1 even for orders with no quantity in this hour.

Answer 1

You are on a right track!

you just need one more layer:

select order_id, customer, max(quantity) hour1 from 
(your query)
group by order_id, customer

Or you can look into how to do PIVOT tables

Answer 2

I question why you would want to take nicely normalized data and put it into a table with that structure. I can understand a query returning the data like that, but another table?

In any case, your problem is a common problem when using correlated subqueries. The table being correlated is included in the subquery. Ooops. Here is fix for that:

insert into Merged_Order_Table(Order_ID, Customer, Hour1)
    select o.Order_id, o.Customer,
           (case when 1 in (select d.Hour from Details d where d.Order_ID = o.Order_ID)
                 then d.Quantity
                 else 0
            end)
    from Orders o;

That said, what you really want is conditional aggregation:

insert into Merged_Order_Table(Order_ID, Customer, Hour1)
    select o.Order_id, o.Customer,
           sum(case when d.Hour = 1 then d.Quantity else 0 end)
    from Orders o left join
         Details d
         on o.Order_ID = d.Order_ID
    group by o.Order_id, o.Customer;